External Factors That Can Affect Fish Disease
Description: The fish disease is one of the negative determinants that hampers the development of aquaculture. Find below the external factors that may contribute to fish disease.
One of the greatest challenges faced by fish farmers is a fish disease. It can potentially lead to significant loss as it slows down the fish growth, increases the feeding expense and prolongs the cultivation period. All of which reduce the quality of the fish.
To prevent that from happening, we need to understand the factors contributing to the development of the fish disease. This article will narrow down its focus on the external factors that can affect fish disease.
When talking about environmental stressors, they basically refer to water conditions. Water is central to the well-being of fish. Water quality parameters which are considered essential include dissolved oxygen, pH, hardness, temperature, ammonia, alkalinity, and nitrite.
Temperature (°C) : 7 – 35
pH : 5.5 – 10
Alkalinity (mg/L) : 50 – 250
Ammonia (mg/L) : 0 – 0.05
Dissolved Oxygen (mg/L) : 3 – 10
Nitrite (mg/L) : 0.02 – 0.6
Hardness (mg/L): 20 – 300
"Suggested water quality criteria for commonly cultured species"
The proportionate amount of each parameter above depends on the cultured species. Failure in complying with the specified parameters can unduly stress fish. Also, fish density affects water quality. The higher fish density equals to the higher likelihood of the water to be in low quality.
Physical stressors have something to do with how you handle, transport, confine and crowd the fish. The inappropriate way of handling or transporting fish may result in skin abrasions or other surface lesions. The abrasions are the sites where pathogens can infect and spread through.
As for crowding the fish, it is about stocking the fish at an appropriate stocking density. Stocking density refers to the number of fish a pond or a container can hold without being overly populated. Overpopulated or inappropriate stocking density yields in the fish struggling for the essentials such as oxygen and food.
After knowing that inappropriate stocking density is harmful to your cultivated fish, you may ask a question as to how to get an appropriate stocking density. As stocking density is all about the balance between water volume and oxygen balance of the pond – not the size of it, the ideal ratio of fish to the water volume should be 1 fish to 2 m3.
Biological stressors refer to other living organisms that inhabit the same confinement as the cultured fish such as other species of fish, micro-organisms, and macro-organisms. One simple yet fundamental rule for successful fish farming is never crowding the cultured fish with potential competitors or predators.
Understanding the abovementioned external factors that can affect fish disease will guarantee a more successful rate of fish harvesting.